Process oe treating metal



BEST AVAILABLE COP.

Nov. '4 1924.

I R. ROBINSON PROCESVS 0F TREATING METAL Filed D86. 6, 1920 Y Y r J I 9I /0// &

BEST AVAILABLE cos.

Patented Nov. 4, 1924.

PATENT OFFICE.

UNITED STATES RICHARD ROBINSON, 0F MASURY, O'HIO.

rnoonss or rnnarmemnrnn Application filed December 6, 1920: Serial No.428,579.

large percentage ofthe ingots made frommetal recovered from open-hearthand other like furnaces are imperfect because of "the piping andsegregation of 'the'ingots, because of the presence of impurities suchas sulphur and phosphorus in a detrimental proportion,-and because ofthe uneven distribution of the cleansing, alloying, or modifying agentsin and throughout the iron or steel; furthermore, a large proportion ofthe finished metal from such furnaces isunsuitable for usebecause of thepresence of Scams therein' The generalobje'cts of this invention are toprovide'a process whereby impurities such as the sulphur and phosphorousconstituents of the'molten mass may be completely and quickly removedand whereby the cleansing, alloying, or other modifying agents may bequickly and uniformly incorporated with the metal, with the result thatI am enabled, not only to produce metal which is uniform or homogeneousthroughout its massand'which is free from the 0bjections abovenoted','-but to produce the same in a much shorter period of time thanis required for the production of the less perfect metal of commerce. Iaccomplish the objects and results referred to in and through anapparatus'such as shown in the" drawings forming a part hereof, whereinFig. 1 represents a central transverse sectional view through a furnacecapable of realizing my'invention;Fig. 2 a sectional plan 'view of saidfurnace; and Fig. 3 a diagrammatic view of the electrical apparatusemployed in connection with the furnace shown in the preceding views.

Describing'the various parts by reference characters, 1 denotes thebottom, 2 the sides, 3 the ends, and'4 the top of a furnace of theopen-hearth type, the bottom being provided with a lining 5 of ganisteror other heat resisting-material. The furnace is provided with the taphole 6 for the removal of metal and with chambers! in' the ends thereoffor'the purpose-of heating air and delivering the same above the bath incon- Projecting downwardly into the'ffurnace junction with gas or oilburners l8.

chamber 29 are a plurality-of heat-resistant tubes 10. Four: such tubesare'shown as mounted two in. each of the sides of the chamber andprojecting downwardly and 130- ward the center'of the hearth. Adjustablyvmounted in .each'ofthe, tubes10 is an electrode 11, the said electrodesbeing shown'as connected? in.:pairs .to electrical conductors Embeddedwithin the bottom wall of the furnace (which may be 'ofmagnesite brick)are a plurality of electro-magnets, four which 12 extending fromopposite sides ofa genermagnets being shown and comprising each acircular core, '14 having a winding '15 therearound. These: magnetsareso arranged that, whenithe' electrodes; 11 are in their inwardlyadjusted positions, the (lower end ofeach electrode will be above thecenter ofa'in'agn'et. Ilf

-With the parts constructed and arranged as described the furnace.willibe charged in the usual manner, with the electrodes-11 elevatedwithin their respective tubes. The charge may comprise the ordinary pigiron, scrap iron and limestone and, if desired, one or more modifyingagents, such as an alloy or alloys or ascavengingagent: The chamber 9and the charge 'will be heated by means of the gas or oil burners 18until the metal is meltedin part at leastand a protecting coating ofslag is formed on top of the metal. The supply of fuel to the burnerswill then be cut off and the electrodes inserted beneath the slag andinto the metal, and preferably with their lower ends close to'the bottomof the latter and 'inproximity to one another, as indicated in Figs. 1and 2. Current will then'be turned on to the electrodes, current alsobeing supplied to thewindings of the'electro-magnets. After the currenthas been turned on to the electrodes, a. scavenging agent (such asspiegeleisen), a degasifying agent (such as fluor as well as in themolten metal, as indicated BEST AVAILABLE COP.

at 16 can; This diffuses uick? action. The m'olten scavenger acts cas;

electrolyte and affords a whirling path of least resistance along whichat least some;

ofithegaseousimpurities move and by which they are delivered tothe-appropriate elec.

trodes, risingialong such-electrodes and being: caught and held by theslag, together with i otherzimpuritieswhich have been carriedalongi-bymuchugas, the scavengenby this 4 tinfehaving-beemgalsi-fiediand caughtiby the 'il Jhr ingi this operation, themetal is pro-2 tectefd from ojxida'tionrby; the-slag coating on 'the-topthereofiiwhileeheated internally at' the bo'ttom ofith'e furnace by the;818C:

trodes. This lbcatiorr ot-electrodes'preyents'. any adhesion of metal tothe bottom (if the" furnace or; to the-elhctrodesi Thismode of treatmentenables any limes stone-and othen ingredient's that maybe atthe bottomof the: furnace to be quickly raised;'and-quickly' liberates impurities1n a: gaseous form, the saidimpurit'iesnbeinga collected by the .slagr,and} where alloying orother modifying agents5 are: employed,-

insures a rapidand 1 uniform: incorporationof the same with the moltenmetal. A=ll=of thel-gase's will be eliminated; thus avoiding piping andsegregation of the:ingots and. seams-in the metal; and thetimeirequi'red' fei makii1g the heat will not eitceedhalf thetimeordinarily-"required for such pur- At the end of the heating by theelecmelf-jany-slag that may have adhered to the si'des 'of the furnace,so as to enable the latter-to betapped;

While-I havedescribd my process with reference to" the: production of.iron and :.=teel','- I- do not" propose to limit the-scope of myinvention to such metals,: as the process-is not only applicable to butvaluable in connection with the treatment of other metals, with suchvariations in amperage suited to the reduction and refining of suchmetals, respectively.

Having thus described my invention, what I'claim is;

1. The process of treating metal which comprises reducing or melting themetal and maintaining the same in a molten condition by means of heatapplied thereto from above, providing a protecting coat-- ing'of slagfor such molten metal, and subjecting;- the molten metal to the actionof an electric current supplied through electi o n:b-y the combustion of.mctal with a protecting coating of slag, and SLIbJGCtlIIgJ the moltenmetal to the action of an electric current flowing therethrough beneaththe slag coating.

.3. The process of treating molten metal a which comprises forming a protecting coat ing of slag, for such metal and subjecting the metal thusprotected to a lcieading action by means of an electric currentpassingtherethrough beneath the saidcoating and adjacent to the-bottomof the. mass of .such,metal and in the presence of one or more modifyingagents.

4; The process of treatinginolten metal which comprises providing thesame with anoxygen or airrexcludingcoating and;subjecting the metalbelow such coating to the action of electrical heating means operatingadjacentto the hottompf the m e tal mass below the said coating andoperating to stirand knead the molten metal charge.

5. The process of treating moltenmetal which comprises providing the samwith an oxygen or air-excluding coating and subjecting the metal belowsuch coatingv to the action of electric current supplied through themetal by electrodes operating adjacent to the bottom of the metal mass.

6. The process of treating molten metal in a furnace which comprisesproviding a mass of such metal with an air or oxygenexcluding coating,and subjecting the molten massbelow such coating to the action ofanelectric current supplied therethrough by electrodes located within andadjacent tothe bottom of such mass, whereby ad hesion of such metal tothe bottom of the furnace or tothe electrodes is prevented and themoltenmetal charge is kneaded. g

7. The process of treatingmetal which comprises preliminarily tusingsuchmetal with slagg-ing material toprovide a protecting coating of slag,supplying electric current to and between electrodes extending into themetal below such coating and through the metal interposed between suchelectrodes, and imparting to the current flowing through such mass. awhirling motion whereby the mass is kneaded and rendered uniform incomposition.

8. The process of'treating metalv which comprises preliminarily fusingsuch metal with slagging material-to provide a-protecting coating ofslag, supplying electric current to and between electrodes extendingBEST AVAILABLE into the metal below such coating and through the metalinterposed between such electrodes, and subjecting the current flowingthrough such mass to the action of an electro-magnet, whereby thecurrent is deflected and the mass is kneaded and rendered uniform incomposition.

9. The process of treating metal which comprises preliminarily fusingthe upper portion of a charge of such metal with slag producingmaterial, thereby to produce a protecting coating of such slag,supplying electric current to and between electrodes extending into themetal below such coating and through the metal interposed between suchelectrodes, and subjecting the current thus supplied to the action ofmagnetic excitation, thereby to impart a whirling motion to thecurrent-in such metal and to the metal itself.

10. The process of treating metal which comprises providing the samewith a protecting coating of slag, supplying electric current to andbetween electrodes extending into the metal below such coating andthrough the metal interposed between such electrodes, in the presence ofa scavenger, and subjecting the current thus supplied to the action ofmagnetic excitation, thereby to impart a whirling motion to the currentin such metal and to the metal itself.

11. The process of treating metal which comprises providing the samewith a protecting coating of slag, subjecting the mass of metal beneathsuch coating to the action of electricity supplied at the bottom of themetal mass through electrodes and in the presence of a scavenger, andsubjecting the current passing between such electrodes and through themetal to the action of one or more electro-magnets thereby to deflectsuch current and impart a whirling motion thereto and to the moltenmetal.

12. The process of treating metal which comprises providing the samewith a protecting coating of slag, supplying electric current to andbetween electrodes extending into the mass of metal below such coatingand through the metal interposed between such electrodes in the presenceof a scavenging agent and a degasifying agent, and subjecting thecurrent thus supplied to the action of one or more electro-magnetsserving to deflect the current and to produce a whirling motion in thesame and in the molten metal.

13. The process of treating metal which comprises providing the samewith a protecting coating of slag, supplying electric current to andbetween electrodes extending into the mass of metal below such coatingand through the metal interposed between such electrodes in the presenceof one or more modifying agents, and discharging impurities in the formof gases along one or more of said electrodes.

14. The process of treating molten metal which comprises providing thesame with a protecting coating of slag, and supplying electric currentto and between electrodes extending into the mass of metal below suchcoating and through the metal interposed between such electrodes in thepresence of deoxidizing and degasifying agents, whereby the impuritiesare discharged in the form of gases along one or more of saidelectrodes.

In testimony whereof, I hereunto aflix my signature.

RICHARD ROBINSON.

